Honda Civic 2018 blind spot information system warning

My Honda Civic 2018 had an accident and it was in a repair shop for a while. After the repair, there was a warning on the dashboard with below icon.

When I asked about this from the mechanic, he took another day to scan it and told me that there is something wrong with a radar sensor in the rear bumper, and told me that he would replace it later because he couldn’t find a replacement sensor at the time. So I took the vehicle home.

A side mirror was damaged in the accident, and I just noticed that they have replaced it with a side mirror which doesn’t have the blind spot indicator. My question is, could this warning shown in the dashboard be a result of using the incorrect side mirror, instead of an issue with the blind spot sensor as the mechanic said?